Flink state backend for TaskManager

问题:

I have a Flink v1.2 setup with 1 JobManager, 2 TaskManagers each in it's own VM. I configured the state backend to filesystem and pointed it to a local location in the case of each of the above hosts (state.backend.fs.checkpointdir: file:///home/ubuntu/Prototype/flink/flink-checkpoints). I have set parallelism to 1 and each taskanager has 1 slot. I then run an event processing job on the JobManager which assigns it to a TaskManager. I kill the TaskManager running the job and after a few unsuccessful attempts on the failed TaskManager Flink tries to run the job on the remaining TaskManager. At this point it fails again because it cannot find the corresponding checkpoints / state : java.io.FileNotFoundException: /home/ubuntu/Prototype/flink/flink-checkpoints/56c409681baeaf205bc1ba6cbe9f8091/chk-14/46f6e71d-ebfe-4b49-bf35-23c2e7f97923 (No such file or directory)

The folder /home/ubuntu/Prototype/flink/flink-checkpoints/56c409681baeaf205bc1ba6cbe9f8091 only exists on the TaskManager that I killed and not on the other one.

My question is am I supposed to set the same location for checkpointing / state on all the task managers if I want the above functionality?

Thanks!

回答1:

The checkpoint directory you use needs to be shared across all machines that make up your Flink cluster. Typically this would be something like HDFS or S3 but can be any shared filesystem.